This invention relates to an assembly and method for delivering and deploying a self-expanding stent, particularly within a lumen of a body vessel. More specifically, this invention relates to the provision of a stent holder to maintain the stent on the catheter assembly during delivery to a stent deployment site and to prevent longitudinal movement of the stent prior to the stent fully expanding.
Stents and stent delivery assemblies are utilized in a number of medical procedures and situations, and as such their structure and function are well known. A stent is a generally cylindrical prosthesis introduced via a catheter into a lumen of a body vessel in a configuration having a generally reduced diameter and then expanded to the diameter of the vessel. In its expanded configuration, the stent supports and reinforces the vessel walls while maintaining the vessel in an open, unobstructed condition.
Both self-expanding and inflation expandable stents are well known and widely available in a variety of designs and configurations. Self-expanding stents must be maintained under positive external pressure in order to maintain their reduced diameter configuration during delivery of the stent to its deployment site. Such pressure may be provided by a sheath overlying the stent.
In using such stents, it is often necessary to position the stent in a precise location within a bodily lumen. Because self-expanding stents have a tendency to move longitudinally before they are fully expanded, accurately positioning the stent in a desired location can prove difficult.
It is a goal of the present invention to provide a self-expanding stent delivery system with improved stent deployment accuracy which prevents longitudinal lurching of the stent during deployment and thereby facilitate the positioning of stents with greater precision. In particular, it is a goal of the present invention to provide a self-expanding stent delivery system having a stent holder which during retraction of the retractable sheath, prevents the stent from substantially moving longitudinally until the retractable sheath has been removed from the stent.